[6.12] Tracing the Mass of Dense Gas in Giant Molecular Clouds

We present wide-field (l\times b=0\,\fdg42\times 0\,\fdg33)
maps of the H^13CN J\!=\!1\!\rightarrow\!0 emission from three major cloud
complexes in the Galactic center. Our goal was to determine
column densities of dense gas using the ratio of integrated
HCN and H^13CN intensities. We compared these values to
those estimated from CO J\!=\!1\!\rightarrow\!0 emission, a common measure of
molecular gas column density. We estimated H_2 volume
densities with an LVG model that includes radiative trapping
(which depends on the column density). We discuss which
cloud regions show reasonable agreement between the two
column density estimators, the implications for calculating
densities, and the application of these results to
single-dish studies of dense gas in external galaxies.

The author(s) of this abstract have provided an email address for comments about the abstract: paglione@inaoep.mx